There are two options for your users when they subscribe: single opt-in or double opt-in. They both have their pros and cons.
Single opt-in is when a user simply types their email address on the signup page of your site and they are automatically subscribed to your email list. Double opt-in is when a user types their email address in and is sent an email with a link the user must click to verify that they would like to join the email list.
Pros: By default, Iterable is designed to support single opt-in subscriptions to lists. It is a simpler process, creates a lower barrier to sign up and is easy for users.
Cons: Any users who misspell their email or otherwise put in a “bad” email address will be added to your list.
Pros: You ensure that you're only sending emails to valid, properly spelled email addresses.
Cons: Additional user friction. There will likely be users that don’t click on the link of the email, and will thus not be subscribed to your list.
Creating a Double Opt-in Sign Up Process with Workflows
The first workflow is sending the two-step verification email:
1. A signup event would trigger the workflow
2. Action node to send the opt-in email to the user (confirmation)
3. When the link in the email is clicked, it leads to a “You are Subscribed” page.
4. When the user clicks the link, you will also send a custom event back to us through the Custom Events API
and call the event something like “emailVerified”.
The second workflow is to add verified users to the master list:
1. The custom event “emailVerified” is the trigger
2. Add user to master list, which is central location for communication
The last step to maintain the Double Opt-in process is to segment all users that don't have an emailVerify event set on their profile onto a dynamic suppression list. This will identify all users that did not complete the second step of the verification process list and prevent them from receiving future blast sends. You can also create a workflow to unsubscribe these users from the Marketing Channel using on a scheduled recurring basis.